/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.catalina.ant.jmx;

import org.apache.tools.ant.BuildException;

import javax.management.MBeanAttributeInfo;
import javax.management.MBeanInfo;
import javax.management.MBeanServerConnection;
import javax.management.ObjectName;
import java.util.Iterator;
import java.util.Set;

/**
 * Query for Mbeans.
 * <ul>
 * <li>open no existing JSR 160 rmi jmx connection</li>
 * <li>Get all Mbeans attributes</li>
 * <li>Get only the Query Mbeans ObjectNames</li>
 * <li>Show query result as Ant console log</li>
 * <li>Bind query result as Ant properties</li>
 * </ul>
 * <br/>
 * Query a list of Mbeans.
 * <pre>
 *   &lt;jmxQuery
 *           host="127.0.0.1"
 *           port="9014"
 *           name="Catalina:type=Manager,*
 *           resultproperty="manager" /&gt;
 * </pre>
 * with attribute <em>attributebinding="true"</em> you can get
 * all attributes also from result objects.<br/>
 * The property manager.length show the size of the result
 * and with manager.[0..length].name the
 * resulted ObjectNames are saved.
 * These tasks require Ant 1.6 or later interface.
 *
 * @author Peter Rossbach
 * @since 5.5.10
 */
public class JMXAccessorQueryTask extends JMXAccessorTask {

	// ----------------------------------------------------- Instance Variables

	/**
	 * Descriptive information describing this implementation.
	 */
	private static final String info = "org.apache.catalina.ant.JMXAccessorQueryTask/1.0";

	// ----------------------------------------------------- Instance Info
	private boolean attributebinding = false;

	/**
	 * Return descriptive information about this implementation and the
	 * corresponding version number, in the format
	 * <code>&lt;description&gt;/&lt;version&gt;</code>.
	 */
	@Override
	public String getInfo() {

		return (info);

	}

	// ------------------------------------------------------------- Properties

	/**
	 * @return Returns the attributebinding.
	 */
	public boolean isAttributebinding() {
		return attributebinding;
	}

	/**
	 * @param attributeBinding The attributebinding to set.
	 */
	public void setAttributebinding(boolean attributeBinding) {
		this.attributebinding = attributeBinding;
	}

	// ------------------------------------------------------ protected Methods

	/**
	 * Execute the specified command, based on the configured properties. The
	 * input stream will be closed upon completion of this task, whether it was
	 * executed successfully or not.
	 *
	 * @throws Exception if an error occurs
	 */
	@Override
	public String jmxExecute(MBeanServerConnection jmxServerConnection)
			throws Exception {

		if (getName() == null) {
			throw new BuildException("Must specify a 'name'");
		}
		return jmxQuery(jmxServerConnection, getName());

	}

	/**
	 * Call Mbean server for some mbeans with same domain, attributes.
	 * with <em>attributebinding=true</em> you can save all attributes from all found objects
	 * as your ant properties
	 *
	 * @param jmxServerConnection
	 * @param qry
	 * @return The query result
	 */
	protected String jmxQuery(MBeanServerConnection jmxServerConnection,
	                          String qry) {
		String isError = null;
		Set<ObjectName> names = null;
		String resultproperty = getResultproperty();
		try {
			names = jmxServerConnection.queryNames(new ObjectName(qry), null);
			if (resultproperty != null) {
				setProperty(resultproperty + ".Length", Integer.toString(names.size()));
			}
		} catch (Exception e) {
			if (isEcho())
				handleErrorOutput(e.getMessage());
			return "Can't query mbeans " + qry;
		}

		if (resultproperty != null) {
			Iterator<ObjectName> it = names.iterator();
			int oindex = 0;
			String pname = null;
			while (it.hasNext()) {
				ObjectName oname = it.next();
				pname = resultproperty + "." + Integer.toString(oindex) + ".";
				oindex++;
				setProperty(pname + "Name", oname.toString());
				if (isAttributebinding()) {
					bindAttributes(jmxServerConnection, resultproperty, pname, oname);

				}
			}
		}
		return isError;
	}

	/**
	 * @param jmxServerConnection
	 * @param resultproperty
	 * @param pname
	 * @param oname
	 */
	protected void bindAttributes(MBeanServerConnection jmxServerConnection, String resultproperty, String pname, ObjectName oname) {
		if (jmxServerConnection != null && resultproperty != null
				&& pname != null && oname != null) {
			try {
				MBeanInfo minfo = jmxServerConnection.getMBeanInfo(oname);
				MBeanAttributeInfo attrs[] = minfo.getAttributes();
				Object value = null;

				for (int i = 0; i < attrs.length; i++) {
					if (!attrs[i].isReadable())
						continue;
					String attName = attrs[i].getName();
					if (attName.indexOf('=') >= 0 || attName.indexOf(':') >= 0
							|| attName.indexOf(' ') >= 0) {
						continue;
					}

					try {
						value = jmxServerConnection
								.getAttribute(oname, attName);
					} catch (Exception e) {
						if (isEcho())
							handleErrorOutput("Error getting attribute "
									+ oname + " " + pname + attName + " "
									+ e.toString());
						continue;
					}
					if (value == null)
						continue;
					if ("modelerType".equals(attName))
						continue;
					createProperty(pname + attName, value);
				}
			} catch (Exception e) {
				// Ignore
			}
		}
	}
}
